Hi,
I have 2 networks defined in the following way:
1. Network with Internet access (virbr0):
Code:
$ virsh net-dumpxml default
<network>
<name>default</name>
<uuid>20675303-c4d4-47ff-b48e-7c099b92dc89</uuid>
<forward mode='nat'>
<nat>
<port start='1024' end='65535'/>
</nat>
</forward>
<bridge name='virbr0' stp='off' delay='0'/>
<mac address='52:54:00:b9:28:35'/>
<domain name='kvm' localOnly='yes'/>
<dns>
<host ip='192.168.122.1'>
<hostname>pc-andtel</hostname>
</host>
</dns>
<ip address='192.168.122.1' netmask='255.255.255.240'>
<dhcp>
<range start='192.168.122.2' end='192.168.122.14'/>
</dhcp>
</ip>
</network>
2. Isolated network, guests can only access KVM host (virbr1):
Code:
$ virsh net-dumpxml hostonly
<network>
<name>hostonly</name>
<uuid>a24cc21a-0b72-4922-b2ab-e0a10a7d372d</uuid>
<bridge name='virbr1' stp='off' delay='0'/>
<mac address='52:54:00:67:cf:fa'/>
<domain name='kvm' localOnly='yes'/>
<dns>
<host ip='192.168.122.17'>
<hostname>pc-andtel</hostname>
</host>
</dns>
<ip address='192.168.122.17' netmask='255.255.255.240'>
<dhcp>
<range start='192.168.122.18' end='192.168.122.30'/>
</dhcp>
</ip>
</network>
When I want the guest to have Internet access I start it with
virbr0 interface, otherwise I start it with
virbr1.
I have NSS configured, so that guests are accessible by host names.
Now, say, the VM is configured with
virbr0 and started. It works as expected:
Code:
$ virsh net-dhcp-leases default
Expiry Time MAC address Protocol IP address Hostname Client ID or DUID
-------------------------------------------------------------------------------------------------------------------
2018-01-08 16:45:02 52:54:00:ae:25:80 ipv4 192.168.122.11/28 slack64-14p2 ff:00:ae:25:80:00:01:00:01:21:e2:c9:a6:52:54:00:ae:25:80
$ ping slack64-14p2
PING slack64-14p2 (192.168.122.11) 56(84) bytes of data.
64 bytes from 192.168.122.11: icmp_seq=1 ttl=64 time=0.146 ms
64 bytes from 192.168.122.11: icmp_seq=2 ttl=64 time=0.367 ms
64 bytes from 192.168.122.11: icmp_seq=3 ttl=64 time=0.260 ms
64 bytes from 192.168.122.11: icmp_seq=4 ttl=64 time=0.232 ms
^C
--- slack64-14p2 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3043ms
rtt min/avg/max/mdev = 0.146/0.251/0.367/0.079 ms
And now, say, the VM is configured with
virbr1 and started. It works as expected:
Code:
$ virsh net-dhcp-leases hostonly
Expiry Time MAC address Protocol IP address Hostname Client ID or DUID
-------------------------------------------------------------------------------------------------------------------
2018-01-08 16:47:34 52:54:00:ae:25:80 ipv4 192.168.122.27/28 slack64-14p2 ff:00:ae:25:80:00:01:00:01:21:e2:c9:a6:52:54:00:ae:25:80
$ ping slack64-14p2
PING slack64-14p2 (192.168.122.27) 56(84) bytes of data.
64 bytes from 192.168.122.27: icmp_seq=1 ttl=64 time=0.258 ms
64 bytes from 192.168.122.27: icmp_seq=2 ttl=64 time=0.318 ms
64 bytes from 192.168.122.27: icmp_seq=3 ttl=64 time=0.331 ms
64 bytes from 192.168.122.27: icmp_seq=4 ttl=64 time=0.325 ms
^C
--- slack64-14p2 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3082ms
rtt min/avg/max/mdev = 0.258/0.308/0.331/0.029 ms
And now, I configure the interface back to
virbr0 and start the machine and it does not work:
Code:
$ ping slack64-14p2
PING slack64-14p2 (192.168.122.27) 56(84) bytes of data.
From 192.168.122.17 icmp_seq=10 Destination Host Unreachable
From 192.168.122.17 icmp_seq=11 Destination Host Unreachable
From 192.168.122.17 icmp_seq=12 Destination Host Unreachable
^C
--- slack64-14p2 ping statistics ---
15 packets transmitted, 0 received, +3 errors, 100% packet loss, time 14332ms
The problem is that, NSS returns hostname for
virbr1, when I would expect it to return it for
virbr0 (both the leases are still active):
Code:
$ virsh net-dhcp-leases default
Expiry Time MAC address Protocol IP address Hostname Client ID or DUID
-------------------------------------------------------------------------------------------------------------------
2018-01-08 16:50:30 52:54:00:ae:25:80 ipv4 192.168.122.11/28 slack64-14p2 ff:00:ae:25:80:00:01:00:01:21:e2:c9:a6:52:54:00:ae:25:80
$ virsh net-dhcp-leases hostonly
Expiry Time MAC address Protocol IP address Hostname Client ID or DUID
-------------------------------------------------------------------------------------------------------------------
2018-01-08 16:47:34 52:54:00:ae:25:80 ipv4 192.168.122.27/28 slack64-14p2 ff:00:ae:25:80:00:01:00:01:21:e2:c9:a6:52:54:00:ae:25:80
Is it possible to solve this problem while maintaining the functionality?
Or if not, is there a way to somehow flush the cache?
Preferably something that would take hostname or dom name as an argument.
For the moment, the only solution I have is:
1. Stop virtual networks.
2. Remove /var/lib/libvirt/dnsmasq/virbr*.status
3. Start the network.
Thanks in advance!
--
Best regards,
Andrzej Telszewski
